Final answer:
When sliding down a slide, you or the slide may become negatively charged based on the material's position in the triboelectric series. Diving into seawater with both types of charged particles moving will not lead to an electric shock. In the case of the metal balls, the negatively charged rod induces opposite charges on them.
Step-by-step explanation:
When sliding down a slide, the question of whether you get negatively charged or the slide gets negatively charged is related to the concept of triboelectric charging, or contact electrification. In essence, when two different materials come into contact and then are separated, one material can become positively charged while the other becomes negatively charged, depending on their positions in the triboelectric series. This series ranks materials based on their tendency to gain or lose electrons.
If you dive into a pool of seawater with an equal amount of positively and negatively charged particles, you would not receive an electric shock simply because of the movement of these charged particles. An electric shock would occur if there was a significant current or a substantial difference in electrical potential, which is not the case in equilibrium.
Regarding the question about the metal balls and the negatively charged rod, ball number 1 would be positive, and ball number 2 would be negative. This is because the rod's negative charge will induce a positive charge in the nearest ball due to the electrons moving away, and these electrons will accumulate on the farther ball. If the second ball is grounded, it will lose its negative charge to the ground, leaving the first ball still positively charged.